After spending the winter months writing fertiliser plans, budgeting and attending technical meetings, my phone is now starting to ring with questions around nitrogen application.
Many customers asked in February if first applications of nitrogen should be applied to oilseed rape, as it’s something that they’ve always done. However, I always suggest it’s advisable not to plan fertiliser applications by a certain calendar date, as weather plays a large role and it varies year-on-year.
I recommend using Green Area Index (GAI), as it’s a great help in crop canopy management. This year, the majority of oilseed rape crops have a high GAI, which means applications could be delayed by a week to 10 days, and growers could apply a smaller amount of nitrogen, reducing their growing and purchasing costs.
The winter wheat crops are establishing well, reaching growth stages 22 to 26. Crops are showing the usual signs of Septoria on the dying leaves, and there has been some yellow rust already reported on some varieties, so vigilance is important.
As soil temperatures are warming up, now is the time to apply herbicide treatments in a bid to control blackgrass and limit its effect on crop yield.
Another weed to be aware of is autumn germinating wild oats. If the field has a history of spring germinating wild oats, I’m always inclined to wait for a full flush, as it only takes one wild oat per m2 to reduce crop yield by 1%.
Crops have established well and are well tillered at growth stages 25 to 29. Most that I have seen are showing signs of nitrogen requirements, and some are indicating manganese deficiency. In terms of weeds to be aware of, I’d recommend to growers to be on the lookout for ryegrass, as this is becoming a big problem in winter barley crops.
Winter Oilseed Rape
Most of the oilseed rape crops are at growth stages 2 to 3, between the rosette to green bud stage. Many appear to have buds visible, which is the cut off point for most herbicide treatments, so growers need to be mindful of this. Thankfully, pollen beetles are yet to be seen, but growers should watch out for pests so that control measures can effectively be implemented if necessary.